The Iron Age 1934-08-30: Vol 134 Iss 9

THE IRON AGE August 30,1934 Editor Managing Editor Consulting Editor News Editor Machinery Editor Pittsburgh Detroit Boston Cleveland Chicago Editor Emeritus Washington Cincinnati Contents Registration You Can’t Prime Pump that Has Leaking Valves Microscopic Analysis Sprayed Metal Metals for Gyroscope Rotors Limiting Power Demand Charge Steel Plant Allowing for Camber Long Single New Equipment News Personals and Obituaries Washington News Automotive Industry Markets Construction and Equipment Buying. Products Advertised Index Advertisers THE IRON AGE PUBLISHING COMPANY President GRIFFITHS, Secretary BAUR, General Advertising Manager PUBLICATION OFFICE: Corner Chestnut and 56th Sts., Philadelphia, Pa. EXECUTIVE OFFICES: 239 West 39th New York, Y., ADVERTISING STAFF Member, Audit Bureau of Circulations Emerson Findley, 311 Union Bldg., Cleveland Member, Associated Business Papers Herman, 675 Delaware Ave., Buffalo, H. K. Hottenstein, 802 Otis Bidg., Chicago Published every Thursday. Subscription Price: Peirce Lewis, 7310 Woodward Ave., Detroit United States and Possessions, Mexico, Cuba, Charles Lundberg, Chilton Bldg., Chestnut $6.00; Canada, $8.50, including duty; Foreign 56th Sts., Philadelphia, Pa. $12.00 year. Single Copy Cents Ober, 239 39th St., New York W. B. Robinson, 428 Park Bidg., Pittsburgh Cable Address, ‘‘Ironage, N. Y.” W. C. Sweetser, 239 W. 39th St., New York D. C. Warren, P. O. Box 81, Hartford, Conn. EIGHTIETH. YEAR SERVICE THE METAL WORKING INDUSTRY NRA CODE 1934 | 4 SHAFT STEEL? manufactures you specify. You get the finest steels steel with that inherent fine grain axles and stands ready can heat-treated give recommend and develop other exceptional combination steels for special requirements. strength, ductility and fatigue- The chrome steels, the manga- resistance. nese steels, the nickel and the regular production, heat after chrome-nickel steels all have steel like this calls for rigid their place according the design control the melting, such can contemplated. But deciding certain analysis for axle- shaft steel means settles the matter. experienced steelmaker, specifications are merely foundation upon which build steel just right for the intended service. When Bethlehem makes your steel for axle shafts you realize the full latent possibilities whatever developed only through years alloy-steel making experience. Bethlehem has had that experience over the entire period during which alloy steels have been used. Whatever the analysis you prefer, you are assured fine parts low manufac- turing cost when your axle-shaft steel made Bethlehem. ESTABLIS nific funds with The saved and earned public aries, never The ment tribute ing,” funds The ing appro: the goods emplo Thi confid essent privat used THE IRON 30, 1934 Page = ——™ x . BETHLEHEM STEEL COMPANY, BETHLEHEM, PA. — — — — —= — — —= = —= = = = = = — —= = => = = PA. THE IRON AUGUST 30, 1934 ESTABLISHED 1855 Vol. 134, No. You Prime Pump That Has Leaking Valves impractical visionaries who are devising the mag- nificent schemes for the dissipation public funds that the pump business cannot primed with public money. SHOULD soon become apparent, even the The reason for this simple. Private dollars, saved through thrift and self-denial earned capable management, have acquired good habits and have learned shun bad company. The hard- earned dollar mortally afraid the easily gotten public dollar that recklessly squandered vision- politicians and world reformers who have never been noted either for earning saving ability. The more profligate expenditure the Govern- ment becomes; the more millions and billions dis- tributes largess under the guise “pump prim- ing,” the less chance there coaxing private funds back into industry and business. The Administration has carried its pump prim- ing experiment for well over year. has poured approximately ten billion dollars into pump with leaking valves. Naturally, has failed utterly tap the great underlying reservoir private capital goods investment funds which recovery and re- employment depend. The valves the business pump are lined with confidence. Unless Government can restore that essential valve lining, there will suction upon private funds, even though the last public dollar used for priming. DOES not make for confidence when year’s drive put men back work has resulted adding one man bureaucracy’s payroll for every two men restored private employment; nor when production and employment are going down the face rising prices and cost living. does not make for confidence when class con- sciousness definitely encouraged legislative and administrative acts and class antagonisms are fos- tered upon unprecedented scale. Nor when the pub- lic sees the laid plans mice and men” the AAA haywire overnight and turn food surplus into serious deficit. does not make for confidence see the Con- stitution sidetracked favor alphabetical con- glomeration boards and bureaucracies which are usurping the functions National and State gov- ernments. Nor hear, week after week, from high places, the proposals for grandiose construction and social schemes that would dazzle the imagination Pharaoh and arouse the envy ancient Roman emperors. needed for recovery not the pro- posed reformation business character but restoration business confidence. Now that the pump priming has not worked, why not examine the valves? ain ‘ive ter gid ire divided form far from new, and much has been written concerning the process during the past decade. However, the various propounders the process dwelt almost exclusively its industrial and aesthetic uses, both real and imaginary. The basic principles involved were largely ig- nored, and practically microscopic strictly technical investigations the sprayed metal particles were made. Taw spraying metals finely course, considerable amount fairly accurate information con- cerning the mechanism the process was collected rule-of-thumb man- ner during the evolution spraying techniques and the development spray pistols, but only cent years has the deposited metal been placed under microscope and studied with regard its texture and adhesion. The following discussion deals primarily with microscopic as- pects the coatings, and the obser- vations contained herein represent elaborations laboratory results reported Dr. Schenk Berlin and Reininger Leipzig. With regard the inception metal spraying, history has that somewhat prior 1909 Dr. Schoop, Zurich, Switzerland, ob- served the apparent welding over- lapped lead bullets which had been fired against wall. subsequent- conducted series experiments attempt simulate the bullet action smaller scale, but was unsuccessful first. Thereupon took already familiar process and obtained fairly good coatings pro- jecting molten metal from crucible means compressed air. The essentials this process, how- ever, had been employed Germany and Switzerland since 1882 means obtaining fine lead powder. The usual method was melt metal crucible, from which issued into gaseous blast which projected the metal rapidly rotating paddle wheel contained within chamber. The action the wheel broke the metal stream, after which the parti- 8—The Iron Age, August 30, 1934 Fig. 1—Several copper particles after be- ing sprayed glass plate. Viewed diameters. cles impinged inner wall the chamber which was kept wet with water film prevent adhesion. The solidified metal particles rebounded from the wall and were collected powder form tank below. This finely divided metal was mixed with liquid and used paint. Since the entire procedure was rather common the time, was strange that one prior Dr. Schoop realized that the chamber wall was kept dry coating metal would formed. Dr. Schoop’s original pistol has modified some extent, but the action today identical with that 1909. this country the Schoop wire pistol was improved the Metals Coating Co. America and its action familiar many. Any metal the form wire can automatically fed into the hot zone blowpipe flame which causes globule molten metal form continuously end the wire. This molten drop atomized blast air, and the particles are driven forward and high velocity impinge the surface coated. apparent that the time inter- val for the vaporization the wire may times result limited speed tempt increase the volume metal available per unit time, well simplify the gun mechanism, Chris- tian Johan Jung developed varia- tion Holland 1928. This instru- ment designated Mellozing pis- tol and distributed Mellowes Co., Ltd., Sheffield, England. has reservoir which can accommodate about lb. metal previously melted independent gas-heated crucible. the original powder-producing apparatus 1882, the molten metal the Mellozing pistol issues from small nozzle fine stream. heated blast air thereupon atomizes the metal and projects forward. There are disadvantages the Mel- lozing procedure. The choice spraying metals limited those which have low melting points, and the pistol necessity constructed metal having high melting point. The result that the finished pistol Fig. 2—Several materials showing variety surface conditions. (1-Bottom) Naturally smooth surface aluminum; same surface after sand blasting; (2) naturally rough surface gray iron; (3) naturally rough surface boxwood; (4) cross-section sand-blasted iron plate; (5-Bottom) iron plate after immersion compared with iameters. heav the makes piece Schoop greater zing enced the coating ture the should melting oped Hollan pistol was gen availal satisfa plac cured. ess use other Zine, \ > x wil ing ty heavy, and the additional weight the molten metal the reservoir makes much more cumbersome piece apparatus handle than the greater speed operation, superior control spraying tem- perature, claimed for the Mello- zing process. This latter fact paramount importance, the quality sprayed coatings greatly influ- enced the nozzle temperature the metal, and very narrow tem- perature range results optimum coatings. For tin the metal tempera- ture should about deg. above the melting point, and for zinc should about deg. above the melting point. third type pistol was devel- oped around 1919 Van Winsen, Holland, for Japanese concern. This pistol melts the metal electrically, and was used the Orient where oxy- gen and acetylene were not always available. Its operation entirely satisfactory, but because economic considerations its worth doubtful places where the gases can se- much for the history the proc- ess and the various types pistols use today. one method an- other practically any metal can reduced liquid form and sprayed practically any type surface. tin and copper are common sheet sprayed (1) with and (2) with Pb. Coatings adhere even after heat- ing 150 deg. for hr. diameters. Fig. 3—(Above): Bronze sprayed the boxwood shown (3) Fig. The bronze enters the wood pores shown the cross-section (below). Dark part wood and light part bronze. Taken diameters. usage for metal protection. Lead has some applications but there are dan- gers poisoning during the spraying process. Aluminum widely used for coating parts subjected heat, salt water spray atmospheric cor- rosion. Monel metal and stainless steel have found place building worn machine parts and surfac- ing high-finish rolls. all cases the molten metal is- sues from the pistol nozzle the form fine cloud which the in- dividual particles vary diameter Fig. 4—Cross-section smooth sheet sprayed (1) with Ni, (2) with Sn, and (3) with Pb. All coat- ings have separated from the sheet following heating. Taken 7.5 diameters. 4 & LIPPERT from 0.0004 0.0006 in., depending the metal being sprayed and the position and kind flame which used. The minuteness these par- ticles may better visualized comparing them with ordinary fog particles which average diameter around 0.00125 in. The fine droplets metal are urged forward the air blast velocities which vary from 300 miles hour about 760 miles hour, de- pending the type blast used and the metal being sprayed. The av- erage these velocities the same order the muzzle velocity low-powered rifle bullet. course the kinetic energies these small particles are very small, but dis- tance in. the velocity sufficient- tening the particle when strikes surface. traveling through the air the particles are streamlined shape. They may not molten, due the cooling action the air, but they are more than likely definitely plastic condition, especially the case metals having high heat content. meeting surface, particular particle flattened out into saucer- shaped disk with ragged edges shown Fig. this illustration can seen several copper particles after impact glass plate. The mean diameter each particle shown Fig. about 0.033 in., and the in. Therefore evident that the in- particles sprayed copper are extraordinarily thin and, com- pared with atomic copper crystals, each particle averages about 100 crys- tals thickness. Metal-sprayed coat- ings, therefore, are built countless number these saucer- shaped particles, and they consequent- test stronger one direction than right angles it. chemically clean and well roughened surface the average adherence the coating the base about seven tons per sq. in. pull normal the surface, according Turner and Ballard. The Iron Age, August 30, 1934—9 lene vire at- etal ria- pis- has late ble. etal izes and ‘ted int. stol = Fig. 5—(Above): The solid crystal ar- rangement casting, compared (be- low) with the loose unhomogeneous piling sprayed particles. The most question ask would be: “Why the individual particles stick the base metal being sprayed?” Naturally there al- loying the junction, the nozzle temperature the spray metal far below alloying level. Therefore the bond purely mechanical nature and consists simple interlocking each spray particle and the base metal. How the metal bound the base clearly shown Fig. wherein sprayed bronze shown intimate contact with boxwood. The actual coating process is, however, not simple the cross-sectional view many would seem indicate. Fig. 6—Sand-like structure sprayed (1) compared with sifted slag sand (2), both diameters. Heaped-up structure sprayed (3) and (4), both un- etched 340 diameters. 10—The Iron Age, August 30, 1934 cases certain metal will not show maximum adherence another sub- stance unless priming coat an- other metal first applied. The box- wood Fig. for maximum ad- hesion, should first sprayed very lightly with tin, then more heavily with zinc, and finally thick bronze layer can applied. With respect the usefulness priming coats, metal spraying similar some proc- esses electro-plating. the metal bond not one cohesion alloying, only logical roughen surface that pre- sents maximum amount area which the spray metal can adhere well furnish small crevices “key-fasts” which the spray par- ticles can lock themselves firmly surface. addition the surface must dry well chemically clean. The realization these factors de- termines almost wholly the success failure metal spraying. The most common method rough- ening smooth surfaces means blasting with special hard sand about 20-mesh grade angular steel shot similar mesh. Germany the same effect often secured treat- ing with about per cent solution some similar etching liquid. all cases the spraying should immediately follow the clean- ing order forestall surface con- tamination due the action the air. Naturally porous materials such cement, wood and plaster require treatment other than the removal all foreign matter from the surface and complete drying. Fig. there are shown variety materials which well illustrate the importance surface treatment. The sand blast- ing aluminum results decided and almost necessary improvement, and iron plate also shown before and after preparation with order demonstrate the neces- sity surface preparation number experiments were made, and the results are shown Fig. Smooth aluminum sheets were coated with Ni, Sn, and respectively, after which they were immersed machine oil 150 deg. for hr. Fig. clearly illustrates how the metals separated from the sheets. However, when sand-blasted sheets were coated and subjected the same oil cycle there was change the contact positions shown Fig. Nevertheless surface might well blasted and still give poor ad- hesion not also chemically clean. This factor which often ignored tyros. For instance, often almost impossible completely cleanse some types used equipment. One foundry company found that cast iron tallow pot practically defied complete cleaning, and another case mercerizer continued seep sulphur after many cleaning attempts. neither case did the spray metal ad- satisfactorily. Like problems would probably arise any metal spraying shop. The mechanism which the spray particles adhere surface has been described, but the interlocking par- ticle with particle somewhat more complex. Fig. there are shown several single particles, and the spraying had continued vidual disks would have piled into moderately compact mass shown 4 ¥ + 4 4 Fig. 7—Sprayed Zn, showing outlines single particles flattened impact. Etched per cent muriatic acid 340 diameters. Fig. However, the structure typically heaped-up nature, and according Reininger can com- pared sand bucket which every space not filled the case shown schematically Fig. this the crystals castings fill each void whereas the spray particles are comparatively loose with many air spaces inclosed within the mass. The sand-like structure sprayed metals directly compared with magnified photographs sand Fig. the same figure are shown and sprayed sections which the heaped structure discernible. One might now ask: “Is the bond between sprayed metal particles also purely mechanical nature there actual cohesion?” There con- siderable divergence opinion whether the spray particles retain least goodly part their heat prior impact with the surface. Micros- scopic examinations lead and tin, which have low melting points, have shown that there often fusion particle with particle. Nev sary the fine injury out hand pistol This that deg. drop the ticles air. must for gen Fig. ticles ture attrib conte! the energ divide ticula siders only spray heat son energ tact most spray of he fusio That parti temp caleu for 763 4 4 | 1 = < i fied hur ad- ems etal ray een ore the idi- Nevertheless temperature neces- sary for fusion seemingly belied the fact that metal can sprayed fine silk tissue paper without injury, guncotton can coated with- out exploding, and the palm the hand can held in. from the pistol nozzle without discomfiture. This would seem indicate then that the case sprayed zinc the temperature has dropped from 420 deg. the nozzle about deg. the hand. This temperature drop could logically attributed the passage the finely divided par- ticles through the low-temperature air. However, the particles impact must above deg. account for apparent fusion. Turner and Bud- gen are the opinion that the par- for aluminum. was subsequently sprayed brass actually only 120 meters per sec. and zine around 140 meters per sec. Obviously these veloci- ties are insufficient result fusion due impact temperature rise alone. However, the temperature undoubtedly elevated somewhat, and that reaction probably adds the temperature the particle (which probably well over the deg. the test) that sufficient energy available fuse metal particles having low melting point. Despite the fusion particle with particle described above, sprayed coating considerably more porous than hot-dip electro-plated surfaces. Porosity extremely undesirable and Fig. Al, Fe, and surfaces which have been polished with rotating wire brushes. Structure much less porous than (3) and (4) Fig. Unetched 340 diameters. ticles during their flight remain semi-molten condition tempera- ture somewhat under 420 deg. They attributed the apparent lack heat content impact with the hand the inability measuring instruments detect such imponderable heat energies contained the finely divided particles. The above assumption not par- ticularly far-fetched when one con- siders that zine has specific heat only 0.09. this basis, single zine spray particle 420 deg. has heat content the order calories, and entirely within rea- son that such minute bundle energy would imperceptible con- tact with the human body which al- most infinitely larger heat capacity. Therefore possible that each spray particle moves within globule heated air and the moment impact the temperature near the fusion point. One other factor has received con- sideration Turner and Budgen. That is, impact the energy ex- change might sufficient fuse the particles. assuming initial temperature deg. C., was that the velocity necessary for fusion when the energy motion converted into heat would 327 meters per sec. for lead, 446 for tin, 763 for 1046 for copper and 1274 may overcome mechanical, ther- mal chemical means the par- ticular case may require. After spraying, the metal particles may consolidated hammering, wire brushing blasting with ball shot. flame give incipient fusion often suits other cases, and this process will discussed later. Also, some cases the interstices can filled pre- cipitating into them certain insoluble chemical compounds. Figs. and there are shown schematically photographically several primary sprayed coatings with typical stratified, unhomogeneous irregular texture. The coatings were treated with rotating wire brushes, and the finer textures resulting from the pressure are shown the same figures. Treatment surfaces neces- sitates considerable investigation order secure the result desired without tearing loosening the coat- ing: Reininger the opinion that the use rotating steel wire brushes preferable, the pressure can more easily controlled and the brushes conform well irregular surfaces. The amount pressure used depends number considera- tions, such the thickness of. the sprayed surface, the extent the sur- face, the kind base metal, and the amount gaseous impurities con- SS Fig. arranged particles sprayed (a) and more compact structure (b) due treatment with wire brushes. tained the pores the sprayed metal. The elimination the porous structure wire brushing shown again Fig. 10, and the views Fig. demonstrate how the brushing also results better contact with the base material. Attention has been called the fact that sprayed metal contains little stage the oxidation occurs. Schoop, Arnold and Reininger are the opinion that oxidation cannot take place during the atomization the gun. They base their conclusions the fact that the metal soon stiffens, and there also little time for oxi- dation due the short period flight, about 0.001 0.002 sec., ac- cording What more likely that oxidation takes place the freshly deposited surface, there time factor and the oxhydrate produced air dampness has con- siderable opportunity penetrate the porous metal prior brushing solidifying hammering. this con- nection Ballard has pointed out that sprayed brass unaltered regards Fig. 10—Porous struc- iron. Same specimen after polishing with wire brushes. Both etched NHs. 340 di- ameters. The Age, August 30, nto ind ich ase his ach are air als ied the lso ior in, its zinc content, and alloys containing phosphorus still contain phosphorus after deposition. some cases the protection af- forded deposited metal can more greatly enhanced suitable heat treatment rather than wire brush- ing shot blasting. The usual pro- cedure subject the coating systematic heat treatment neu- tral gas use open flames and some form protective coating for the metal. The result melt soften the sprayed surface, but care must taken not oxidize it. The single particles are, therefore, longer Fig. 11—Cross-sections showing surface contacts sprayed metals. Fe. Contacts (1) and (2) are not very close, but (3) and (4) are moderately close. (Below) After polishing with wire brushes; (1) Fe, (2) Al, (3) Al, and (4) Fe. Surface contacts bottom views are much superior those above. All specimens unetched and magnified times. just sticking together, but the entire surface becomes homogeneous mass which alloyed with the base metal somewhat the same manner hot- dip coatings. The thermal process finds its great- est use aluminum coatings. Base metals, such and Cu, alloy with the aluminum shown Fig. 14. The entire process consists spray- ing heavy aluminum coating and then aluminizing the surface heat- ing 700 1000 deg. Oxidation prevented covering the surface with brine solution, bitumen some other special The Fe-Al alloy surface non-scaling 950 deg. and has long life 1000 deg. The actual alloying the two metals can seen the cross-section micro- photograph Fig. 14. This method now finding considerable applica- tion means protecting other metals against high-temperature oxi- dation. With regard the actual strength sprayed coating which has been brushed, the inquiry often made its ability withstand bending 12—The Iron Age, August 30, 1934 and elongation stresses. For simple expansion contraction, the slight give the interlocking bond suffi- cient take all the stresses, pro- vided the article not. subjected changes. Likewise, the metal coating will not disintegrate under light flexures, but high-degree bends will result breaking the surface. This shown Fig. 12. These views taken about diameters show the type fractures which occur the point maximum stress ex- treme bend. However, for bends moderate size the sprayed coatings generally stand well average hot-dip coatings. great danger brushing metal coatings the application exces- sive pressures. the coating ham- mered, brushed ground too severely, the metal crumbles from the base. microscopic investi- gation this weakness shown Fig. 13, wherein excessive pressure resulted the metal separating from the base 0.09 0.15 mm. The splitting off under excessive pressure does not occur uniformly but appears first isolated sections the sur- face. This explained Heyn the theory hidden elastic tensions. brief, certain particles are only slightly deformed and have the ability being additionally deformed pressure. Between the particles there are hidden elastic tensions when pressure applied, and when re- moved the forces act the direction least resistance. Sometimes this action works toward greater adhesion places and splitting off other places. After the coatings have been con- densed some type pressure treatment, the density still less than the same material when cast rolled. the other hand, the hardness the sprayed metals often exceeds that the solid metals. The sprayed metal also slightly more brittle, although can filed, turned and milled, but liable flake one direction. When copper sheet sprayed with copper and then rolled, the sprayed metal splits into long shreds. That is, ductile one direction but cracks being subjected transverse stresses. Other tests more comparative nature have been made England. (Above) (1) Fe, (2) Al, (3) Al, and (4) brass Similar iron rods were coated, one with sprayed and another hot galvanization. They were elongated until cracks appeared. The sprayed coating withstood per cent elonga- tion whereas the galvanized coating failed per cent. Two lengths steel rod were prepared the same manner and then turned lathe. The galvanized coating flaked off when quite thin, but the sprayed was turned down almost zero thickness without any apparent strip- ping off. addition, sprayed zinc coatings can withstand seven im- mersions aqueous solution cop- per sulphate without any red copper deposit showing. Likewise similar coating withstood cycles hr. each mist salt spray before the first sign rust appeared. The above corrosion tests would seem indicate that well applied sprayed films which have been brushed will withstand penetration liquids. However the average sprayed coating must thicker than hot-dip coating equally water-resistant. order wholly satisfactory sprayed Fig. metals. compre film two but coats, The coating depend metal ample, the stainle dom coat necess: hig least lard practi Aft done metals experi tain prior perim this are coatin spray brush comp! ing acter tions the meta! petiti meta great ordin xX . | at} 1 Sprayed Coating Base F Fig. Bending test sprayed metals. (Above left): coating the compression side, and (above right) the coating the tension side. film must non-porous: Theoretically two coats lead tin are sufficient, but for stainless steel takes eight coats, and for monel, twelve coats. The average thickness single coating varies from 0.001 0.003 in., depending the melting point the metal used. Lead and tin, for ex- ample, cover great deal thicker than the harder metals such monel and stainless steel. have complete free- dom from pores, Ballard states that coating least 0.0025 in. thick necessary for lead, whereas for metals higher melting point coating least 0.010 in. thick necessary. Bal- lard also claims that tin and zinc are practically non-porous sprayed. After this review actual work done the structure sprayed metals, interest note the experimental investigations now under way, reported Reininger. cer- tain amount heating surface prior spraying beneficial and ex- periments are being conducted along this line. Also, German experimenters are studying the effect tempering coatings brine baths order get simple, non-expensive method increasing the homogeneity sprayed coatings. The amount pressure applied polishing brushes being correlated, and more complete study under way concern- ing the relations between the char- acter sprayed platings and condi- tions spraying, such distance the pistol nozzle, temperature vaporization and speed projection the particles. concluding, may stated that metal spraying only negligibly com- petitive with established methods applying protective ornamental metal coatings. Its cost obviously greater than standard procedures for ordinary uses, but there are many special cases which the spraying gun the only means applying metal coating, and there are other cases where conditions favor its use and make economical. Its particular sphere usefulness applying coatings large ob- jects situ where the object cannot brought stationary plant for galvanizing electroplating. Again, many objects are too large put plating-out tank. For many years the practice metal spraying the United States has not had the range application has had European countries, par- ticularly Germany. those coun- Fig. 13—Cross-section showing the results too great pressure during polishing. (Above) coating split about 0.15 mm. from sheet, and (below) coating split about 0.09 mm. from sheet. Both specimens unetched and viewed diameters. tries many procedures have been established and successful operation has been secured for number years. occasion concerns the United States have reported that metal spraying has not entirely ful- and upper part Fe-rich. Etched HNOs. Taken diameters. filled expectations. general, how- ever, too much was expected the procedure and many cases not enough attention was paid the rules which successful cleaning, spraying and polishing. That is, the process appeared simple paint spraying, whereas should con- sidered similar electroplating with which necessary. Now that the in- itial cost apparatus has been low- ered, expected that domestic con- cerns will make fuller use the op- portunities metal spraying which are available. Record World Consumption Tin ONSUMPTION tin the tin- plate industry amounted 55,000 tons the year ended last May, the highest total recorded for similar period, accord- ing advices received the Com- merce Department. This, pointed out, 5000 tons more than 1929 and 2800 tons excess the peak year 1933. World consumption tin during the 1933-34 period amounted 129,- 600 tons against 101,765 tons the corresponding period immediately pre- ceding. The United States increased its consumption tin from 38,470 tons the months ended May, 1934, 58,117 tons the 1933-34 period, while British consumption ad- vanced from 17,879 tons 20,112 tons. Consumption tin the world’s motor car industry during the first five months the current year reached total 5700 tons, compared with 3590 tons the corresponding period 1933. The figures cited above are from the July bulletin The Hague office the International Tin Research and Development Council, the report points out. Dark section pure iron The Iron Age, August 30, 1934—13 4 . 14—The lron Age, August 30, 1934 Rough steel ingot for disk for 13-ft. rotor for stabilizer the “Conte Savoia.” The ingot gradually formed into round, with discards taken from time time. meta tion. has now equi cent mat gyroscopes were first developed about years ago. Both metallurgy and physics, they have presented many and difficult problems regards construction and opera- tion. Meanwhile use the apparatus has rapidly expanded, especially recent years. Vessels large and small now have stabilizers and gyroscopic compasses, and airplanes own the equipment, particularly the form automatic pilots, which have re- cently created some sensation. Wiley Post, his phenomenal airplane trip around the world, used the first auto- matic pilot ever made. every type gyroscopic appara- tus, metals are used extent little dreamed the average individual. And the variety metals and alloys employed for numerous parts ex- tensive. Not less than different metals enter into the construction gyrocompass. Very exacting are the conditions under metals and alloys are used and hence their properties and conditions must guaranteed the nth power perfection. One the vital parts each type gyroscopic apparatus the metal rotor, wheel, the gyro- scope itself. This must travel high rate speed ranging from 910 revolutions per minute the largest ship stabilizers and 930 r.p.m. 5600-ton yacht 14,000 r.p.m. some the smaller gyroscopes other applications. The metal which incorporated the rotors, which the main spring vital part gyroscope, mat- ter what the size, determined largely the size the gyroscopic large ship stabilizers, smaller vessel stabilizers gyros, gyroscopic com- passes, automatic and on. general there are four classes material which the rotors are made: plain carbon steel, alloy steel, manganese bronze, and brass. The rotors range size from the largest emphasize this point that, mat- ter what material used, the rotor metal must brought the highest possible state uniformity density, strength, composition and forth, because mass metal, whether large small, traveling the speeds which they are called operate, might otherwise fly apart run unbalanced state. Per- fect balance the speed revolu- ARGE size, homogeneity metal, dynamic and static bal- ancing, precision assembly, such bringing bolts identical ten- sion—these are some the prob- lems making the rotating ele- ments for stabilizing gyroscopes, such are used for steadying ships. different metals enter into the construction gyrocompass. tion sine qua non—and this secured only after extreme care. Both forgings and castings are, have been, used for these rotors and the metallurgical problems involved in- sure what may regarded nearly absolute uniformity the metal are many. The largest rotors are installed such vessels transatlantic liners and large ocean-going yachts. The most illustrious case the Conte Savoia the Italian Line, 41,600 ton ship. this vessel there are three stabilizers. Each one contains large rotor, ft. diameter and weighing 110 tons, which turns 800 r.p.m. when operating normal speed, with maximum 910 r.p.m. The interesting fact about this in- stallation that three such stabilizers were adopted rather than one which would have required 18%-ft. rotor have accomplished the same pur- pose. But today impossible obtain from the steel companies forging 18% ft. diameter which will meet the specifications because, allowing for all discard and losses, large enough steel ingot cannot made. From the largest possible ingot obtainable today 13-ft. rotor the best that one could count on, when all specified conditions discard, ma- chining and forging are fully met. One not dealing here with ordi- nary forging. the early history the development the manufacture these rotors, steel castings were used but they did not prove reliable uniform forgings. But just that time, large enough forgings were not secured. illustrate the methods used producing these large rotors, the gen- eral principles which are the same for all sizes when made steel, the details involved the production the 13-ft. ones for the Conte Savoia lustrated. large steel ingot mild carbon steel poured the conventional manner from open-hearth furnaces into ingot mold with hot top. These are usually octagon ingots and fluted, illustrated. The ingot then put through the usual forging steps, during which unusually heavy discards are made, retain the soundest metal. After rounding and forming, the metal rolled into the shape disk. After rough machining, the disk then heat treated carefully bring the metal its best physical prop- erties. Then finished-machined. Counting the discards, the loss from scaling and from machining, not more than per cent, often less, the original steel ingot remains the disk. The physical properties the metal measure the standard for com- positions this character, properly heat treated: tensile strength rang- ing from 75,000 85,000 per sq. in. with corresponding elastic ratio and ductility. But such prop- erties are not the essential char- acteristics, the factor safety this respect being ample. more vital The Iron Age, August 30, ABOVE The forging process the steel into rough disk. RIGHT After rough machin- ing and heat treating, the disk now un- dergoing finish ma- chining. 16—The Iron Age, August 30, 1934 importance the uniformity the steel, for slight variation this the shape seriously affects the equilibrium the rotor re- volves high speeds. This state- ment applies all rotors any metal. Ship stabilizers large ones for the Conte Savoia require the joining together two large disks into one rotor wheel. Where the stabilizers are smaller, single disk suffices. the case the three rotors for the three stabilizers the Italian liner, two disks, each about 22% in. thick (13 ft. diameter) and weighing 109,000 lb. each, are joined together special method devised the engineers the Sperry company. (Sperry Gyroscope Co., conception and difficult its applica- tion but these conditions are neces- sary insure final rotor that dependable. When Rotor Made Two More Disks important that the bolts which secure together the various units tightened the exact calculated amount and all the same amount that the units are held together with the same tension, thus equaliz- ing the stress each bolt. ac- curat sired ments fore ening curat furni ing disk place rim drive only the twee the relat larg pass thes cent inse leng tigh usec mea cent sion slot the ing unt tior — curate method securing this de- sired result micrometer measure- ments the length the bolt be- fore and after tightening, the length- ening the bolt furnishing ac- curate indication the stress and furnishing ready means equaliz- ing the stress all the bolts. The rotor may made two more disks, which are machined abut only adjacent the securing bolts. These which pass completely through the disk assembly are symmetrically placed around the section near the rim and are made that they are drive fit the bore the bolt holes only the position abutment the disks. There also placed be- tween the disks, split ring key, the purpose which prevent relative displacement the disks when operating and consequent shear- ing the bolts. For securing the shaft the rotor, large machine screws are used. They pass through holes bored the flange the shaft and are threaded into tapped holes the rotor. Each these screws provided with small central hole extending through most its length and into which may inserted means measuring the length the screw before and after tightening. The gage ordinarily used employs indicator which measures accurately the depth the central hole from some base dimen- sion, say the bottom the screw slot. The procedure measure the length each bore before tighten- ing and then tighten each screw until has elongated predetermined amount calculated give certain stress, exceeding the stress that may placed the bolt due opera- tion the stabilizer. The most the scope the determination its balancing whether uniform throughout that will revolve without vibration wabbling. One the illustrations shows the world’s largest balancing machine for ascertaining whether rotor dynamic and static bal- ance, single 11-ft. disk rotor for the yacht Savarona, shown under test, which typical for all such tests. this case, was found that bring the rotor into satisfactory bal- ance, only 46% oz. metal one side and oz. the other side had accuracy approximately 0.01 ounce-inch per 1000 rotor weight. This eloquent testimony the uniformity the steel and the exactness the machining. should added that, were there any porosity, inclusions defects the metal, such balancing would not have been realized and the expensive forg- ing would have had rejected. For the small rotors, similar appara- The larger rotors are bring all bolts identical tension and keying prevent one disk rotor, 109,235 net loss metal, 108,765 lb., 49.8 per cent. Total weight the stabilizer 110 gross tons, the vessel having displace- ment 5600 tons. The Sperry company states that “experience with all stabilizers (on ships) has shown definitely that = ade assembling two more disks, with rotating with respect the other. Some idea the amount metal involved the manufacture the larger steel rotors can secured from the following facts: The 13-ft. rotors for the Conte Savoia: Total weight original in- got, 256,500 net weight finish- machined half section, 109,000 net loss metal for both sections com- plete rotor, 295,000 57.5 per The 11-ft. rotor for the Savarona: Total weight original ingot, 218,000 net weight finish-machined per cent the roll eliminated; that, general, the larger the vessel, the more efficiently can stabilized and that, with vessels 5000-tons displacement more, the deck can held within deg. the horizontal the heaviest seas ordinarily en- countered.” Besides their incorporation ocean liners, large merchant vessels and ocean-going private yachts, they are being used naval vessels the United States, Japan and other na- tions. One Japanese airplane carrier The Iron Age, August 30, 1934—17 the the re- ‘ — 18—The Iron Age, August 30, 1934 Bolts unite the shaft stubs the rotor, shown this view complete rotor assembly for Conte Savoia has had for eight years stabilizer equipment slightly smaller than one the three the Conte Savoia. recent years their use air- planes has broadened decidedly. Composition Rotor Metal The metal used variaus rotors for gyroscopic apparatus deter- mined the size the gyroscope employed. indicated, mild plain carbon steel used the larger stabilizers. Other metals used are follows: Steels: molybdenum steel forging containing about 2.50 per cent Ni, 0.70 per cent and 0.60 per cent Mo. This steel, after careful processing treatment, has the erties: Tensile strength, 158,000 Ib. per sq. in.; 140,000 per sq. yield point; elongation in., 15.5 per cent; Brinell hardness, 340. Rotors this alloy steel, after finishing, are initially balanced speed 6000 r.p.m., then given stretching run hr. 12,000 r.p.m. and then finally balanced. These are in. diameter, in. wide and weigh ap- proximately lb. each. They are used gyrocompasses. Vanadium steel forgings simi- lar properties and dimensions are also used, Manganese Bronze: Rotors this the ancing, the rotor bearings supported live rubber pads which permit oscillations one plane. The disk speed identical with the natural period vibration the sup- ported mass and the natural period the rubber. This allows the pulses due centrifugal forces give the systema large and measurable amplitude tion. inal mater equall the homog They found Ace mang billets long. These appro finish they namic lines New its the parat and The and Platt, this the Deuts year only See a : and faces are tested material used made castings. the foundry practice large heads, equalling most cases the weight the rotor, were provided insure They were made the company’s own foundry. According present practice, the manganese bronze purchased billets, in. diameter and in. long. These are cut into four These blanks are then forged the approximate size and shape the finished rotor. After finish-machining, they are balanced statically and dy- namically special methods. After being initially balanced 5000 r.p.m., rotor assembled rotor case and given stretching run 9000 r.p.m. for hr. then replaced the balancing stand and given the final balance. Such rotor in. diameter and in. wide. weighs approximately The composition and properties the manganese bronze are here tabulated. Brass also rotor metal. The conventional product used. But the preparation the rotors, the same care adhered to, establish substantially absolute uniformity. New York Industry Museum Increasingly Popular HAT science museum developed along what may called modern lines has strong appeal the people indicated the experience the New York Museum Science and In- dustry. Three aims are held respect its exhibits, namely, make clear the mechanical operation each ap- paratus, set forth the scientific principles involved the operation, and suggest the economic and so- cial importance each division. The attendance 1933 was 234,319, and pointed out Frederic Platt, president the museum, that this figure represents per cent the number visitors the famous Deutsches Museum Munich the year 1932-33. Yet the display space Deutsches Museum. addition the exhibits portraying the evolution basic industries and utilities, sound and silent motion pictures scientific and industrial subjects are commonly shown every noon hour and after- noons except Sunday, and reference library devoted invention and in- dustrial progress maintained. The museum occupies the fourth floor the Daily News Building, 220 East Forty-second Street, New York, with some 30,000 sq. ft. floor space. handicapped the fact that there direct entrance from the street level, the case with public institution its character. Its present status owing largely funds bequeathed Henry Towne, head the Yale Towne Mfg. Co., Manganese Bronze for Gyroscope Rotors Chemical Composition: Per Cent Manganese 3.50 max. Other elements 0.20 max. Physical Properties: Tensile strength, per sq. in..... 65,000 Yield point, per sq. 30,000 Elongation in., per .20.0 Reduction area, per Weight per cu. in., ........ 0.3009 Shrinkage per 0.25 Brinell hardness 102 Specific gravity 8.34 and has been helped also the Carnegie and New York Founda- tions. needs municipal and general public help, particularly the shape building well located and large enough serve the needs. spite the times, important ex- hibits were added 1933 the per- manent displays. Among these, Dr. Charles Richards, executive vice- president the museum, reports the following: Railroad air brake ap- paratus donated part the West- inghouse Air Brake Co.; gear cut- ter and shaper placed automatic operation regular, clock- controlled intervals; operating and illuminated model showing the action each stroke four-cycle internal combustion engine; pictorial repre- sentation electric power system showing its use industrial applica- tions. The Iron Age, August 30, 1934—19 ia. le- el, - lb. = n., — in p- re 30 gs fe )- re 1e a modified watthour meter, besides measuring the energy taken from the power feeders, sends impulses recording demand meter, which turn, prede- reached, serves stop the pushers the rolling mills practically all plant managers who buy power from central sta- tion. very easy for indus- trial plant pile heavy irregular power requirements, creating abnor- mal needs for energy entirely out proportion the average demand. limitation power demand Central stations are required in- dustry have available sufficient gen- erating capacity meet the maxi- mum demand all times, even though they may actually called upon deliver energy for high peaks during comparatively short time. Since the central stations have cer- tain percentage their available gen- erating capacity tied meet ex- cessive peak loads, has been the practice many cases charge their customers not only for the actual power used, but addition for the demand. spite this demand charge the central stations are anx- ious cooperate with the industrial plants reducing the demand be- cause their equipment can utilized more advantageously operated somewhere near continuous capacity than merely held readiness meet possible peak. Power demand can reduced 20—The Iron Age, August 30, 1934 Limiting the Power Westinghouse Electric Mfg. Co., Chicago can also controlled automatically equipment the market today. The manner which the River- dale, plant the Acme Steel Co. limited its power demand charge considerable interest. They found that staggering the operation their mills they could reduce the pow- peaks materially. However, since their production necessitated the over- lapping the mills, they invariably had high peaks. Control 30-Min. Intervals further study was made and was found that the demand, which based intervals, could automatically controlled installing demand limiting equipment consisting totalizing impulse sender, and im- pulse receiver recording demand meter and various relays. The impulse sender modified watthour meter and serves two pur- poses. First, measures correctly the energy taken from the feeders and, second, sends impulses the impulse-operated recording demand meter. The sender equipped with three-wire contact mechanism that generates the impulses which are sent the receiver. The receiver totalizes the impulses from the sender. recording demand meter with the electrical ele- ment replaced notching relay which actuates the gear train and advances the gearing definite dis- tance for each impulse. has pen reset solenoid and adjustable